Patriarch of Grado

Throughout their history, the patriarchs of Grado, with the support of Venice, fought military, politically, and ecclesiastically the patriarchs of Aquileia, who were supported by the Lombards, then the Carolingians and the Holy Roman Emperors.

[3] The dispute between Grado and Aquileia was partially resolved in 1132 by Pope Innocent II, who restored many of the traditional episcopates to Aquileia, including the Diocese of Istria, while giving Grado the Venetian Lagoon, Split, and the Dalmatian islands of Arbe, Veglia and Ossero.

[4] After 1349, the patriarch of Grado and his subordinates were chosen by the Venetian Senate, and the names merely sent to Rome for confirmation.

[3] In 1451, with the papal bull Regis aeterni, Nicholas V merged the see of Grado with Castello to form the Archdiocese of Venice.

[5] The Patriarchs often resided in the church of San Silvestro in Venice where they were officially 'visitors', since canon law did not allow them to reside permanently in territory of another diocese (Venice was part of the Diocese of Castello).